Carts, such as grain carts, can be used to shorten harvesting time by improving the efficiency of harvesting equipment such as combines. Such carts can, for example, be used to transport grain from harvesters or combines in the field to grain trucks or bins at the side of the field. Carts are often preferred for use compared to grain bins or grain trucks because grain bins are typically immobile and grain trucks typically do not perform well in muddy or rough field conditions and have the potential to spark fires in dry fields. Carts usually comprise a bin (e.g., a container, hopper, or box) sitting atop a wheeled frame in combination with an auger means or mechanism for unloading grain from the bin. Carts can be designed to handle soft or rough fields with ease and can be designed to be drawn by a tractor alongside a combine that unloads its contents into the cart.
Carts can be used to enable a combine to continue to harvest while unloading the grain into the cart. This grain unloading arrangement can increase productivity dramatically because combines need never stop to unload. In addition, it is not necessary for the combines themselves to travel to grain trucks or bins at the side of the field each time the combine is full. After a cart is loaded with grain or other material by one or more combines, the grain is unloaded from the cart into a bin for temporary storage or into a waiting grain truck for transport to another location, such as a grain elevator. Because carts offer a combination of economy, versatility, production savings, and maneuverability, they have been widely accepted by farmers and widely produced by equipment manufacturers.
Carts capable of unloading grain directly into a grain truck or bin often use a conveyor to do so. Often the conveyor is in the form of an auger. Various auger configurations are known. Auger structures can, for example, be contained inside the hopper structure, located entirely outside of it, or in another desired location. Auger configurations can, for example, have a single auger or multiple augers. The auger structure can, for example, be located at the front, side, back, corner, or another desired location of the cart.
In a dual auger grain cart, a lower, horizontally disposed drag auger can, for example, receive material from the hopper and deposit it into an upper, vertically disposed lift auger. The upper auger can then, for example, carry the material received from the lower auger and deposit it into a trailer, such as a grain trailer. Triple auger configurations are also known, which can include, for example, a lower, horizontally disposed drag auger, a vertically disposed lift auger, and an upper, horizontally disposed discharge auger. A typical auger for a grain cart includes an auger screw that is housed inside a tubular housing. Typically, there is a drive mechanism used to drive the horizontal and vertical augers that is coupled to the horizontal and vertical augers. For example, the drive mechanism coupled to the augers may cause the auger screws to turn.
In a dual auger type grain cart, the vertical auger may be limited to discharging grain on one side of the grain cart. In such a situation, an operator is limited during an unloading operation, and must unload from the side of the grain cart where the vertical auger is located. Accordingly, some grain carts offer the ability for the vertical auger to discharge on either side of the grain cart (e.g. on the left side or the right side). To do so, the vertical auger needs to be able to move between a left-side discharge position and a right-side discharge position. Typically, left or right is determined from the perspective of a cab operator sitting in a cab of a tractor pulling the farm implement. For such a cart capable of unloading on either left or right sides, a drive mechanism for the two augers needs to function when in both the left-side and right-side discharge positions.
Some known dual auger grain carts drive the horizontal drag augers from the front of the vertical housing by extending a shaft through the vertical auger housing. In such carts, the horizontal drag auger shaft extends through the vertical housing, thereby forcing the vertical auger to be offset, or positioned below, the horizontal drag auger drive shaft. The offset vertical auger arrangement increases the height of the drag auger centerline, which may increase the height or length of the hopper, thereby raising the center of gravity of the grain cart such that the grain cart is less stable. Alternatively, grain carts that include an offset arrangement between the vertical auger and the horizontal auger drive shaft may include a wider frame, tongue, or hitch to accommodate for the spacing between the offset augers. Widening the frame, tongue, or hitch, however, hinders the maneuverability of the grain cart and requires more material for constructing the grain cart, which increases the overall cost of manufacturing. Other double auger carts position the drive assembly between the vertical and horizontal augers. This drive assembly can be external or internal relative to the auger housings. This arrangement requires that the drive assembly for the augers extend beyond the corresponding auger centerlines, which does not allow the flighting rotation to operate beyond the opposite auger's centerline. For example, the vertical auger flighting cannot extend beyond the horizontal auger centerline, and the horizontal auger flighting cannot extend beyond the vertical auger centerline.
Still other double auger carts drive the horizontal auger from the rear end of the grain cart. This drive system requires at least one drive shaft with support bearings running alongside the horizontal auger; and a set of sprockets with roller chain, belt pulleys with belts, or gearboxes, to transmit power over from the drive shaft to the horizontal auger centerline. In some other conventional double auger carts, the drive system typically includes a motor disposed on the back of the drag auger.
Known dual auger type grain carts and their corresponding drive systems have additional shortcomings. For example, in carts where the horizontal drag auger shaft extends through the vertical housing, the vertical auger is offset from (e.g. positioned below) the horizontal drag auger drive shaft. In this arrangement, if such carts are used to unload from both sides, one of the unload positions (e.g. left or right) would have the vertical auger being offset above the horizontal auger drive shaft. This auger arrangement creates a substantially flighting-free space in the transition zone (e.g., junction box area) between the horizontal and vertical augers, thereby increasing the likelihood of grain getting stuck or compressed at the transition zone. The collection or compression of grain at the transition zone causes grain damage, higher wear on the auger flighting edge, uneven distribution of grain material through the auger housing, and a higher amount of grain material stuck at the transition zone.
As another example of a shortcoming, in carts where the vertical auger flighting does not extend beyond the horizontal auger centerline, the flighting's operating zones cannot operate below the centerline. That means that grain must be pushed in spaces around the drive mechanism that are free of flighting. These substantially flighting-free spaces may be to the sides of the drive mechanism, above the drive mechanism, or some combination of both. As mentioned above, this substantially flighting-free space in this transition zone (e.g. junction box area) between the augers is undesirable. Additionally, with the grain being pushed up and/or around the drive mechanism, there would be a higher level of grain compression, which can result in further grain damage. Still another example of a shortcoming, is that in carts where the horizontal auger is driven from the rear end, mechanisms, such as drive shafts universal joints and gearboxes, are frequently used to convey the power from the front of the unit to the rear of the drag auger, resulting in added cost, maintenance and complexity. Furthermore, if the vertical auger pivots to adjust the unload discharge height or moves to unload on both sides, at least one additional driveline assembly would be needed to transmit power from the vertical auger gearbox to the driveshaft driving the horizontal auger. Furthermore, the driveline assembly typically includes uneven driveline joint angles to accommodate for the movement of the vertical auger. The uneven driveline joint angles, however, may cause high angular velocity variations between the auger assemblies or even curtail the operability of the auger assembly.
Accordingly, there is a need to provide improved dual auger type grain carts.